Liquid dispensers, such as soap and sanitizer dispensers, are configured to provide a user with an amount of liquid material upon the actuation of the dispenser. Many liquid dispensers use dome pumps that provide a compressible void that receives the liquid material from a replaceable refill container. Correspondingly, when the dispenser is actuated the dome pump is engaged, or otherwise compressed, whereupon the material within the void is pushed out and dispensed through an outlet tube for delivery at a dispensing nozzle. Simultaneously, with the dispensing of the material, a low pressure region is formed within the void of the dome pump, causing new material from the refill container to be drawn into it. As such, the operation of the dome pump ensures that there is a continuous amount of material ready to be dispensed from the dispensing nozzle upon the compression of the dome pump.
While current dome pumps utilized by dispensers provide acceptable dispensing performance, it lacks a system to prevent residual material retained in the outlet tube from inadvertently drooling or otherwise leaking out of the dispensing nozzle. Such drooling occurs primarily due to the viscosity of the material being dispensed, the temperature of the material (which becomes more viscous with increased temperature), and the operation of gravity. In addition, drooling results in a substantial amount of wasted material, which increases operating costs, as such dispensers require more frequent refill container replacement. The drooled material also results in an unwanted mess in the region where the dispenser is mounted, such as on countertops and the floor. In some cases, the drooled material may create slippery areas on the floor beneath the dispenser, creating a slip hazard to those walking thereabout.
Therefore, there is a need for a shut-off system for a dispenser to prevent residual material from drooling out of a dispensing nozzle. In addition, there is a need for a shut-off system for a dispenser that is simple to implement. Moreover, there is a need for a shut-off system for a dispenser that is low-cost. Still yet that is a need for a shut-off system for a dispenser that can be retro-fit to an outlet tube provided by a pump assembly, such as a dome pump assembly.